12 TRANS. ST. LOUIS ACAD. SCIENCE. 



the Pliocene, can scarcely be doubted since the discoveries in 

 California reported by Prof. Whitney. Nor can it now admit of 

 question that men lived on the shores of the Delaware and on the 

 eastern coasts as far back as the glacial period, to which the stone 

 implements discovered by Dr. Abbot in the gravels of that river 

 have been assigned. It is equally certain that men lived with the 

 mastodon in the times of the Loess of the Missouri valley, as 

 proved by the recent discovery by Dr. Aughey, in Iowa and Ne- 

 braska, of mastodon bones and flint arrow-heads lying together 

 in that deposit under such circumstances as to exclude the possi- 

 bility of later driftings ; not to mention similar discoveries of the 

 late Dr. Koch in alluvial river bottoms in Missouri, where such 

 driftings were possible. Human remains have been found, also, 

 in Postpliocene caves in Brazil and Buenos Ayres. But hitherto 

 none have been discovered in Miocene deposits on this continent. 

 To the eastward of that great Pliocene lake that extended along 

 the Rocky Mountain range from whei^e the gulf of Mexico now 

 is far northward into British America, neither human nor ele- 

 phant remains have been found in Pliocene or any earlier depos- 

 its. It was not until the end of the Pliocene that this ancient 

 barrier was cut ofl'by the further elevation of the continent; and 

 then only is it probable that either man, or the mastodon, or the 

 megalonyx and other South American types of animals, could 

 cross to the eastern portion of North America ; and it is in Post- 

 pliocene deposits only that their remains are found in that area. 

 No anthropoid apes have ever been found anywhere on the con- 

 tinent of America. Thus, while it is certain that man existed in 

 the Miocene period on the other continent, the earliest evidences 

 of his existence on this continent belong to the Pliocene of the 

 Pacific coasts ; and this fact points to the Pliocene land connec- 

 tion across Behring's Straits as the pathway by which he reached 

 America. 



The question now is, in what part of the earth the human type 

 first appeared. Hitherto, geologists have pointed to Southeast- 

 ern Asia as the most probable place of origin ; and some writers 

 have imagined a sunken Le7nuria in the Indian Ocean. Prof. 

 Owen has significantly intimated that the Australian negroes are 

 a survival of one of the oldest races of the earth in those remote 

 islands where they have found protection from the aggressions 



